Basically, the failing delayed test would fire two web requests during
the proceedings. In unfortunate timing, the first would succeed and the
test would think "everything is okay", but the actual request loading
results has not yet run.
This check ensures *something* is loaded, which seems to be enough to
make things reliable.
`TestSceneBeatmapSkinFallbacks` was locally caching a `GameplayState`
instance to fulfill dependencies of a
`SkinnableTargetComponentsContainer`. However, it was doing so using
`new TestBeatmap()`, which is a raw decoded beatmap that hasn't been
converted to any ruleset yet, which was causing failures in
`BeatmapDifficultyCache.GetTimedDifficultyAttributesAsync()` as that
method is expecting to receive a post-conversion, ready-for-gameplay
beatmap.
Resolve by proxying forward dependency instances from the
already-known-to-be-working `actualComponentsContainer`.
`TestSceneStatisticsPanel` intends to check the operation of statistics
panels using dummy ruleset classes. However, `StatisticsPanel` relies on
being able to retrieve the playable beatmap, which requires a converter.
One was not provided by the dummy rulesets, therefore the retrieval
would fail with an unobserved exception.
To fix, add a barebones converter implementation that is enough for the
test to pass.